1. Field of the Invention
The present invention relates to a method and to a device for the measurement of two orthogonal electromagnetic field components on the basis of a cross coil, and for evaluating the components during the distance measurement in electronically guided vehicles.
2. Discussion of the Prior Art
An arrangement of that type is disclosed in German Pat. No. 30 15 954, in which an antenna constructed as a cross coil serves to two-dimensionally scan the magnetic field of a pilot cable which is positioned in the roadway. The antenna signals are finally correspondingly processed in order to provide for the steering of the vehicle. For vehicles which are steered in this manner, an adequate monitoring must be provided to ensure that the vehicle will not be endangered in the event of the failure of a system component of the vehicle. In the above-disclosed known arrangement there is provided a diagnostic field having a predetermined amplitude and frequency is superimposed on the pilot cable field, through which there is generated a test signal for the monitoring of the antenna arrangement. In this manner there is indicated any malfunction in the steering control system, so as to enable the driver to undertake appropriate measures, when in the use of this known arrangement there is encountered a failure of the receiving antenna the steering control will be spontaneously interrupted.